ProjectParameters Class
Represents parameters that control how features are reprojected from one Crs to another.
NuGet/Assembly: Carmenta.Engine.5.16.2.nupkg (in the CECore assembly)
Syntax
public class ProjectParameters : EngineObjectRemarks
A ProjectParameters instance can be used to modify how a ProjectOperator or Feature.ProjectTo reprojects features from one Crs to another, but the default values will usually suffice.
Reprojection can also occur implicitly in an OrdinaryLayer, or in operators other than ProjectOperator. These implicit reprojections will use a ProjectParameters that has the default values (expect that the RasterBitdepthExtensionAllowed will be True). If you need to modify such reprojections, you must insert an explicit ProjectOperator in the operator chain. (Or possibly a custom operator or a ScriptOperator that calls Feature.ProjectTo.)
Line and polygon features
It may seem obvious that the edges of a line or a polygon feature are straight lines. But the earth is round, so what do we mean by a straight line on earth? Among many possible answers, Carmenta Engine normally uses the simplest one: an edge of a line or polygon feature is a straight line in its coordinate reference system. That is, a straight line is something that is drawn with a ruler on a plane map. But a line that is straight in one coordinate reference system will be curved in most other coordinate reference systems. To produce a curved image of an originally straight line, extra points must be inserted on the line. By changing the ProjectOperator.ProjectParameters of a ProjectOperator, you can control the distance between the extra points (EdgeLengthMax), and exactly when they will be inserted (EdgesToSegmentize).
If you disagree with this definition of straight lines, and prefer a great-circle path (the shortest route), you should use the GreatCircleOperator. Or if you want a rhumb line (a curve of constant azimuth), you can use the fact that rhumb lines are straight in a MercatorProjection. You can also use the Crs.Route method to generate rhumb lines or great circles.
Raster features
When reprojecting a raster feature, it would be inefficient to reproject the center point of each cell in the raster. To save computation time, it is accepted that reprojected raster cells can be slightly displaced, up to the limit specified by the RasterDisplacementMax property.
Point and mesh features
How points and mesh features are reprojected is not affected by ProjectParameters.
Inheritance Hierarchy
System.Object (not available in C#)
EngineObject
ProjectParameters
Platforms
Windows, Linux, Android
ProjectParameters Members
The ProjectParameters type has the following members.
Constructors
| Name | Description |
|---|---|
| ProjectParameters | Initializes a new instance of the ProjectParameters class. |
Properties
| Name | Description |
|---|---|
| EdgeLengthMax | Gets or sets the maximum length of an edge in a line or polygon Feature. |
| EdgesToSegmentize | Gets or sets a value that determines which features will get extra points. |
| IsDisposed | Gets a value that tells whether the current ProjectParameters has been disposed. Inherited from EngineObject |
| NativeHandle | Gets the native Carmenta Engine kernel object the current ProjectParameters represents. Inherited from EngineObject |
| RasterBitdepthExtensionAllowed | Gets or sets a flag indicating if the raster format may be changed to accommodate a new undefined value. |
| RasterDisplacementMax | Gets or sets the maximum allowed displacement of a raster cell. |
Methods
| Name | Description |
|---|---|
| Clone | Creates a copy of an object. Inherited from EngineObject |
| Dispose | Releases the reference to the native Carmenta Engine kernel instance the EngineObject represents. Inherited from EngineObject |
| Equals | Determines whether this instance is equal to another. Inherited from EngineObject |